The present invention generally is related to film handling arrangements for sheet film view cameras and the like. Large format sheet film view cameras have been used for some time by professional photographers. A standard 4.times.5 inch sheet film view camera and/or other large format sheet film view cameras are likely to be in the inventory of almost all professional photographers. For many commercial photographic assignments, such as photographs of architecture, landscapes, advertising models and advertising displays showing products, large format film is the best practical way to obtain the high quality photographs expected of commercial photographers.
Large format film cameras exhibit certain disadvantages as compared with small format roll film cameras, especially with respect to the photographer's convenience. Coupled with the large format of the sheet film to be used are relatively large, heavy and bulky camera components which must be transported to and from the site where the photographs are to be taken. Typically, the view cameras are mounted on a tripod and include universal adjustment possibilities for the orientation of the sheet film plane and the lenses so as to facilitate the optimum exposure of the sheet film in a precise manner. Typically the view camera will have a lens assembly mounted at one end of camera frame rails to be slidably and pivotably oriented with respect to the frame rails over a wide range of possible planes and angles. At the other end of the camera frame rails, a camera back for accommodating the sheet film holder assembly is mounted. The sheet film holder assembly is also mounted to be movable in a variety of planes and angles. Typically, the camera back assembly and the lens assembly section are mounted for relative axial movement with respect to one another along the camera frame rails. An expandable light tight bellows interconnects the lens assembly or camera head and the camera back assembly.
The LINHOF and SINAR brand cameras are exemplary commercially available view cameras of the type referred to herein.
The camera back assemblies of these view cameras include a so-called "ground glass" or "viewing glass" disposed adjacent the plane where the film will be when it is exposed, which viewing glass can be viewed from behind by the photographer to see the image which is to be photographed. The photographer adjusts the orientation and location of the camera head and its lenses and the camera back which is to hold the sheet of film to be exposed, by manipulating the various adjustment controls on the camera back and camera head while observing the image projected on the viewing glass.
Until recently, the film sheets themselves were carried in a rigid film holder which was adapted to slide into a lateral opening in the camera back to a position in front of the ground viewing glass after the camera was appropriately adjusted for taking a picture. Once the film holder was inserted into the camera back, a light tight slide was then removed laterally from the forward facing side of the film holder to allow exposure of the film by operating the shutter of the camera. Traditionally, the film holders held a pair of sheets of film which faced opposite of one another in the holder and were covered by respective light tight slide covers that could be manipulated by the photographer to accommodate exposure of the film and subsequent light sealing of the holder and film, and removal of the film holder from the camera. With these two sheet film holders, the photographer would simply remove the holder from the camera and invert the holder to accommodate exposing the second sheet of film. These rigid film holders being downloaded in a dark room after exposure. New sheets of film had to be uploaded in the holders in a dark room for subsequent shooting.
Certain disadvantages of the above-mentioned rigid reusable sheet film holders were avoided by the film package and holder arrangement described in commonly assigned U.S. Pat. No. 4,725,865 to Hoffman (Hoffman '865 Patent). In this Hoffman '865 patent, the sheets are housed, not in a reusable rigid film holder, but rather in a disposable envelope package. This envelope package solves many of the problems with the prior rigid holders in that the bulk of the film containers is substantially reduced as compared to the prior art holders. Also, a disposable film package is used, which itself included a light sealing slide envelope that could be manipulated in the camera backs and film holders, and removed in a light tight manner from the film holders, without requiring any dark room environment. It was thus possible to accommodate transportation to remote locations of a large number of sheets of film, without the bulkiness of the prior rigid reusable holders and without the need for downloading and uploading sheets of film into such holders at a remote location where the dark room environment was either inaccessible altogether or, at most, most inconvenient. These and other advantages are described in the Hoffman '865 patent.
The Hoffman '865 patent also describes a holder that is insertable in a view camera camera back much in the same manner as the prior art rigid holders were inserted. However, this holder includes provisions for accommodating the use of the disposable package, including provisions for accommodating the manipulation of the package envelope so as to facilitate insertion and anchoring of the film sheet for exposure and subsequent reclosing of the package and withdrawal of same.
Commercial embodiments of the Hoffman '865 patent film package and holder are now being marketed by KODAK under the product names READYLOAD and READYLOAD HOLDER.
Commonly assigned pending U.S. Patent Application Serial No. 07/279,079, filed Dec. 2, 1988 discloses a further film holder which is also especially advantageously adapted for accommodating the disposable film packages of the type described in the Hoffman '865 patent, as well as the disposable film packages marketed under the mark "Prochrome" by Polaroid Corporation. In this holder arrangement, manually operable closing mechanisms are provided for selectively clamping the film package serving to facilitate the insertion into the holder and anchoring of the package, the sliding movement of the outer envelope of the package to facilitate exposure of the film and the reclosing and removal of the light tight envelope with the exposed film.
In many instances, a professional photographer makes test exposures of the scene being photographed, by using instant process photographic films such as Polaroid film. Thus, after setting the camera in a ready-to-photograph position, with appropriate orientation of the film plane and the camera lenses, the photographer uses Polaroid instant film/print products to make one or more test photos to determine that the film and lens orientation, as well as the light settings and composition, are optimum. Prior art arrangements for accommodating such instant photography test photos include the Polaroid 545 holder which is insertable in a view camera back in much the same manner as the above-discussed rigid sheet film holders. However, the Polaroid 545 holder includes rollers for compressing the Polaroid film developing chemicals, which are contained in "pods" integral within film envelopes, so that the print/film image is instantly developed upon removal from the holder. This Polaroid 545 holder can also accommodate non-instant sheet film packs including the disposable film package disclosed in the Hoffman '865 patent.
The above-described film-handling arrangements, including the use of the disposable packages with the substantially reduced bulk of material that has to be transported to remote sites and the flexibility of using and carrying more different types of film emulsions than previously was the case are quite advantageous. However, inconveniences and problems with view cameras still remain. For example, in those arrangements where the film package and/or film holder has to be inserted in the camera back after the camera is set in position for taking a photograph, the manual manipulations required may disturb the camera setting. That is, even though a perfectly aligned and focused image appears on the viewing glass, and/or video screen monitoring the image to be photographed, prior to the insertion of the film package and/or film holder, this precise positioning and alignment can be disturbed due to the inherent forces acting on the camera when one manually manipulates the devices for loading the film and pulling the light slide and/or the light tight envelope to accommodate exposure. Also, with these manually operable arrangements wherein the camera and the film holder or envelope must be also manually contacted by the photographer while the film is being changed, difficulties arise with respect to obtaining a precise registration of the film sheet in the same exact location for different packages of film and/or different holders being inserted into the camera at the same setup. Most times, multiple shots of the same scene, with different camera settings and/or different film emulsions, is desired, thus it often occurs that multiple film changes are desired at a single specific setting of a physical location of the film plane in the camera. Thus these problems regarding possible movement of the film holder and/or small changes in the exact registration location of the sheet of film, are important.
Another problem with film handling arrangements for large format sheet film cameras relates to the "leveling" of the film holder so that the film plane is exactly perpendicular with the local earth "tangent". In many instances the base upon which the camera tripod or other mount must be placed is an uneven surface, thereby tilting the film plane with respect to the true level position. For this reason, many prior art view cameras are provided with level indicators where the photographers can look at a carpenter's level bubble or the like to determine if the film holder and camera is actually level. However, these prior level indicator devices require that the photographer interrupt his viewing and composing on the viewing glass or video image of the picture to be taken so that it is difficult, if not impossible, to simultaneously precisely compose and focus the image while also precisely leveling the film plane. Also, some camera positions make viewing the levels difficult or impossible. Further, most studio work is in low light, so levels are often hard to see and read.
An object of the present invention is to avoid the above-discussed problems with respect to the convenience of handling sheet film changes and the possibility of disturbing the set position of the film plane. Another object of the present invention is to readily facilitate the simultaneous composition of images to be photographed while also maintaining the film plane in a precise level position, if required.
These and other objects and advantages of the invention are achieved according to the present invention by providing film holder arrangements which include two relatively movable holder parts defining a film sheet accommodating cavity therebetween, which parts are movable between an open position for accommodating insertion and withdrawal of the film and/or film package and a closed position for clampingly securing the film sheet in position and accommodating exposure of the film, wherein a control mechanism is provided for moving the first and second holder parts between the open and closed positions without the application of reaction forces that can cause camera movements, whereby a preset desired film plane position is maintained, even with multiple film sheet changes at the same set film plane location. In especially advantageous embodiments of the invention, the control mechanism for controlling the movement of the two film holder parts includes pneumatic driving devices which provide for a smooth, jerk-free loading, exposing, and unloading of the sheets of film. Certain preferred embodiments of the pneumatic models can be manually operated, dispersing with the need for electrical power. In other preferred embodiments, the holder control mechanism includes electric motor-driven actuators for moving the first and second holder parts between the open and closed position.
According to certain preferred embodiments of the invention, the simultaneous focusing and composition of the image to be photographed and the leveling of the film plane is facilitated by the provision of a non-optical level warning system which apprises the photographer of any deviations of the film plane from a predetermined level film plane orientation. This arrangement avoids an interruption of a photographer's observation of the image to be photographed on a viewing ground glass, video display or the like. In especially preferred embodiments, the alarm system is an audible alarm system which emits an audible signal whenever the film plane is out of a predetermined acceptable level range. The present invention contemplates different embodiments for activating the level alarm, including mercury bubble tip switch constructions and pendulum switches.
Preferred embodiments are contemplated wherein the film holder is provided as part of a detachably attachable camera back, which camera back is provided with an integrated light metering system for both strobe and ambient light as enters the camera back via the taking lens. In preferred embodiments, the light metering system includes electrical data interface means to communicate with automatic lens assemblies for the remote setting and function control thereof.
In certain preferred embodiments of the invention, the above-mentioned level alarm features and the film holder control features are combined in a single camera back. In certain preferred embodiments, the camera back is designed as a standard attachment for existing view cameras utilizing the "international" GRAF-LOK system; and includes the control systems for facilitating loading, exposing and unloading the sheets of film, the level alarm system, and provisions for optional viewing of the image to be photographed on a ground glass screen or via an external video display. In certain preferred embodiments, the film holder arrangement includes pressure roller squeezing devices for optionally utilizing instant photography processed film such as Polaroid film. This mentioned optional feature accommodates the desire of many photographers to be able to take test or "proofing" photographs preliminary to the final conventionally processed photographs.
Preferred embodiments are contemplated which include integral light meter measuring both strobe and ambient light with automatic computation of F-stop and speed choice. A bar code reader on the film pack/holder facilitates automatic accommodation of different film emulsions.
Those preferred embodiments that include a single unit replaceable camera back with automated features for accommodating the loading, exposing and unloading of the film package, as well as the level alarm and optional video viewing features, all cooperate together to provide an extremely convenient and reliable film handling arrangement for meeting the demands of even the most demanding professional photographers.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.